This relates to producing end-to-side anastomoses, particularly in communication with coronary arteries. Accordingly, distal anastomosis fittings and associated devices are disclosed.
Current techniques for producing anastomoses during coronary artery bypass grafting procedures involve placing a patient on cardiopulmonary bypass support, arresting the heart, and interrupting blood flow in order to suture, clip or staple a bypass graft to the coronary artery and aorta. However, cardiopulmonary bypass support is associated with substantial morbidity and mortality.
This invention provides devices and methods to avoid bypass support by allowing for positioning and securing bypass grafts at host vessel locations without having to stop or re-route blood flow. In addition, this invention mitigates risks associated with suturing, clipping or stapling the bypass graft to a host vessel. This may be accomplished, in part, by features adapted to avoid bleeding at graft attachment sites and avoiding collapse of a host vessel around the incision point. Further, the invention optionally provides features to improve blood flow within a graft and increase the patency of a graft.
In performing cardiac bypass surgery, anastomosis sites are typically provided at a proximal site along a patient""s aorta, and a distal site along a coronary artery beyond a partial or complete occlusion. Producing an effective anastomosis along a coronary artery is particularly challenging. The outer diameter of a coronary artery where a distal anastomosis may be needed can range from between about 1 mm to about 4 mm in size. By way of comparison, the outer diameter of the aorta where a proximal anastomosis may be located ranges between about 20 mm and about 50 mm in size.
The relatively small size of the site for a distal anastomosis translates to greater difficulty in a number of ways. Basic surgical challenges are encountered in dealing with the smaller vasculature. Further, an interface issue is introduced. Often, particularly for connection with the smaller coronary arteries, a graft conduit will have a larger diameter than the host vessel. This may be due to the need for a larger diameter conduit to carry adequate blood flow or the result of using a saphenous vein which must be inverted for use due to its valving, thereby orienting the larger end of the graft toward the distal site. For whatever reason, the mis-match in size in joining the graft to the coronary artery must be dealt with. The present invention is adapted to handle these issues as well as others as may be apparent to those with skill in the art. The distal-type connectors described herein may be employed with precision and speed, resulting in treatment efficacy not heretofore possible.
The invention includes various improvements in end-side anastomosis systems. Particularly, connectors for producing distal anatomoses are described. They each include a fitting comprising a rear section with a segment that is deflectable about a hinge section to allow for placement and securing the device. Curvilinear side and forward-facing portions are preferred. Most preferably, these portions are configured to conform to the shape of a host vessel. Such a fitting may alone serve as a connector between a host vessel and a graft. Alternately, the connector may comprise a fitting in combination with a collar adapted to secure a graft to the fitting.
Various features for improving the deployability of a connector, hemostasis at the connector and blood flow through a graft may be provided by the invention. Further, various tools for use in preparing for and creating an end-side anastomosis may comprise part of the invention.
While connectors and deployment devices according to the present invention are preferably used in coronary artery bypass grafting procedures, particularly at a distal location, it is to be understood that the systems described herein may be used for purposes other than creating distal anastomoses. The systems may also be used to produce anastomoses between bypass grafts and host vessels to treat other occlusions, vascular abnormalities such as stenoses, thromboses, aneurysms, fistulas and indications requiring a bypass graft. The system of the present invention is also useful in bypassing stented vessels that have restenosed, and saphenous vein bypass grafts that have thrombosed or stenosed. Further, the invention may have other applications, such as producing arterial to venous shunts for hemodialysis, bypassing lesions and scar tissue located in the fallopian tubes causing infertility, attaching the ureter to the kidneys during transplants, and treating gastrointestinal defects (e.g., occlusions, ulcers, obstructions, etc.).
The present invention variously includes the devices as well as the methodology disclosed. Furthermore, it is contemplated that subcombinations of features, especially of the connector features disclosed, comprise aspects of the invention.